There is nothing wrong with using a pick. Many well know bass players use them exclusively. It is a good idea to work on finger style as well though. As far as learning new songs and techniques are concerned, you can take lessons, buy videos or books and keep doing what you have been doing. memeorize the fretboard and understand where each note is and where the octaves are. As your playing improves and you become more comfortable, work on learning the various scales. Listening to songs and using tablature. Be patient. It takes a long time to learn any instrument but you are on the right track. Good luck